Nitrobenzene compounds, particularly 2,6-disubstituted nitrobenzene compounds, are widely known as intermediates for the synthesis of various organic compounds, as described above. Particularly, 2,6-dichloronitrobenzene is reported as an intermediate for synthesis for producing a compound described as an EP4 receptor antagonist (see Example 55, Patent Literature 1), or as an intermediate for synthesis for producing a compound described as a brakykinin B1 receptor antagonist (see Example 8 and Example 104, Patent Literature 2). In addition, it is also known as an intermediate for synthesis for producing a hair dyeing composition (see Production Example 6 and Example 10, Patent Literature 3).
Similarly, 2-chloro-6-alkoxycarbonylnitrobenzene is also known as a beneficial intermediate, and is known as an intermediate for synthesis for producing a compound described as an inhibitor of protein tyrosine phosphatase (see Example 76, Patent Literature 4), or as an intermediate for synthesis for producing a compound having high herbicidal activity {see (2)-(5), Synthesis of Compound 2, Patent Literature 5}.
Further, it is also known that 2-chloro-6-methoxymethylnitrobenzene, which is a useful intermediate for an agrochemical, can be produced from 2-chloro-6-alkoxycarbonylnitrobenzene by subjecting it to methylolation by reduction, followed by methoxymethylation (see Patent Literature 6).
With regard to nitrobenzene compounds from which useful compounds can be produced as described above, it has been conventionally known that in the oxidation of an aniline compound to a nitrobenzene compound with industrially inexpensive hydrogen peroxide, the reaction proceeds easily in the oxidation of the aniline compound to the nitrobenzene compound when the ortho position with respect to the amino group of the aniline compound is not substituted (Patent Literature 7). However, when an attempt is made to conduct the oxidation of a 2,6-disubstituted aniline compound under the same conditions, the target 2,6-disubstituted nitrobenzene compound cannot be obtained with good yield (see Comparative Examples 1 and 2). Therefore, conventionally, it has been necessary to use high concentration hydrogen peroxide, which requires much caution in work, and further use a high risk organic peroxy acid such as peracetic acid or trifluoroperacetic acid in order to obtain a 2,6-disubstituted nitrobenzene compound from a 2,6-disubstituted aniline compound (Non Patent Literature 1 and Non Patent Literature 2), and there has been no synthesis method for producing a 2,6-disubstituted nitrobenzene compound under mild conditions.